Tuesday 17 December 2013 14.59 EST
First published on Tuesday 17 December 2013 14.59 EST

It is deemed to be a good thing, generally speaking, for senior executives to take nonexecutive positions at other companies: it exposes the individual to other ways of working, and broadens the mind.

But there is a time and a place for taking a day off from the day job. It is baffling that Alison Brittain, head of Lloyds Banking Group's retail division, can think this is the right moment to join the board of Marks & Spencer as a nonexecutive director.

Last week Lloyds was fined £28m by the regulator for running a crass incentive-and-demotion scheme that put branch staff under intense pressure to stuff customers with unwanted investment products. Coming so soon after the PPI scandal, the episode has done huge damage to Lloyds' attempt to create a reputation for treating customers fairly.

Brittain, it should be said, did not design the absurd "grand in the hand" bonuses: she arrived at Lloyds in September 2011 and was instrumental in calling a halt to the silly system. Even so, encouraging a change of culture at Lloyds looks to be a bigger challenge than it did last week. Lloyds shareholders might prefer her to give it her undivided attention.

M&S shareholders may also view the appointment as odd. The retailer's personal finance division is run in partnership with HSBC, a direct competitor to Lloyds. So Brittain will have to put her hands over her ears whenever M&S Bank crops up in boardroom discussions.